Search

Arsenic contamination of soils threatens the health of millions globally through accumulation in crops. While plants detoxify arsenic via phytochelatin (PC) complexation and efflux of arsenite from roots, arsenite efflux mechanisms are not fully understood. Here, white lupin (Lupinus albus) was grown in semi-hydroponics and exudation of glutathione (GSH) derivatives and PCs in response to arsenic was scrutinised using LC-MS/MS. Inhibiting synthesis of PC precursor GSH with L-buthionine sulfoximine (BSO) or ABC transporters with vanadate drastically reduced (>22%) GSH-derivative and PC2 exudation, but not PC3 exudation. This was accompanied by arsenic hypersensitivity in plants treated with BSO and moderate sensitivity with vanadate treatment. Investigating arsenic-phytochelatin (As-PC) complexation revealed two distinct As-PC complexes, As bound to GSH and PC2 (GS-As-PC2) and As bound to PC3 (As-PC3), in exudates of As-treated lupin. Vanadate inhibited As-PC exudation, while BSO inhibited both the synthesis and exudation of As-PC complexes. These results demonstrate a role of GSH-derivatives and PC exudation in lupin arsenic tolerance and reveal As-PC exudation as a new potential mechanism contributing to active arsenic efflux in plants. Overall, this study uncovers insight into rhizosphere arsenic detoxification with potential to help mitigate pollution and reduce arsenic accumulation in crops.

Nickel is an important element utilized in various industrial/metallurgical processes, such as surgical and dental prostheses, Ni-Cd batteries, paint pigments, electroplating, ceramics, computer magnetic tapes, catalysis, and alloy manufacturing. However, its extensive use and associated waste production have led to increased nickel pollution in soils and water bodies, which adversely affects human health, animals and plants. This issue has prompted researchers to develop various optical probes, hereafter luminescent/colorimetric sensors, for the facile, sensitive and selective detection of nickel, particularly in biological and environmental contexts. In recent years, numerous functionalized chemosensors have been reported for imaging Ni2+, both in vivo and in vitro. In this context, metal-based receptors offer clear advantages over conventional organic sensors (viz., organic ligands, polymers, and membranes) in terms of cost, durability, stability, water solubility, recyclability, chemical flexibility and scope. This review highlights recent advancements in the design and fabrication of hybrid receptors (i.e., metal complexes and MOFs) for the specific detection of Ni2+ ions in complex environmental and biological mixtures. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is an abiotic stressor negatively affecting plant growth and reducing crop productivity. The effects of Cd (25 μM) and of pre‐soaking seeds with salicylic acid (SA) (500 μM) on morphological, physiological, and glycerolipid changes in two cultivars of wheat (Triticum aestivum L. ‘Tosunbey’ and ‘Cumhuriyet’) were explored. Parameters measured were length, fresh and dry biomass, Cd concentration, osmotic potential (ψ), lipid peroxidation, and polar lipid species in roots and leaves, as well as leaf chlorophyll a, carotenoids, and fv/fm. Fresh biomass of roots and leaves and leaf length were strongly depressed by Cd treatment compared to the control, but significantly increased with SA + Cd compared to Cd alone. Cd reduced leaf levels of chlorophyll a, carotenoids, and fv/fm, compared to controls. Treatment with SA + Cd increased pigment levels and fv/fm compared to Cd alone. Cd treatment led to a decrease in DW of total membrane lipids in leaves and depressed levels of monogalactosyldiacylglycerol and phosphatidic acid in leaves and roots of both cultivars. The effects of SA priming and SA + Cd treatment on lipid content and composition were cultivar‐specific, suggesting that lipid metabolism may not be a primary target underlying SA remediation of the damaging effects of Cd on wheat growth and development. [ABSTRACT FROM AUTHOR]

Phosphorus is a very important plant nutrient for the development of plants and its production is not unlimited in the world. In addition, excessive use can lead to soil and water pollution. In this respect, phosphorus should be used effectively in plant production, especially in calcareous soils. The aim of this study was to comparatively determine the effects of phosphorus-enriched organomineral fertilization (p-OMF), chemical phosphorus fertilization (CF), and organic fertilization (OF) on some chemical properties of a calcareous soil. The experiment was established in Söke county of Aydın province in the Southwest of Türkiye. In this study, four doses of dairy manure (DM1: 10, DM2: 20, DM3:30, and DM4: 40 t ha−1) in OF, four phosphorus doses (P1: 10, P2: 20, P3:30, and P4: 40 kg P ha−1) in the CF system, and sixteen different doses of OMF formed by the combinations of these two fertilizers were applied excluding control. According to the main research findings, p-OMFs increased the soil organic matter (SOM), salinity, total nitrogen (N), available phosphorus (P), and potassium (K) by 60.1%, 20.9%, 22.1%, 140%, and 17.2%, respectively. They also decreased soil pH by 4%. As a result, it was determined that the most effective organomineral fertilizer combination that maintains soil properties at appropriate levels in calcareous soils is DM3+P2 (30 t ha−1 dairy manure +20 kg P ha−1). [ABSTRACT FROM AUTHOR]

Agricultural practices such as extensive manure application (containing residual antibiotics) as fertilizer can also contribute to antibiotic pollution in soil, besides nitrous oxide (N2O) emissions. This dual impact designates certain agricultural soils as hotspots for heightened N2O emissions and antibiotic pollution. Nevertheless, our understanding of the repercussions of antibiotic residues on N2O emissions and the underlying mechanisms remain elusive. This comprehensive literature review investigated recent research findings regarding antibiotic contamination in agricultural soils and its influence on microbial N2O production and consumption. We scrutinized published data and field experimental monitoring results to analyze the prevalence and temporal variation of antibiotic residues in Chinese agricultural soils. By analyzing 482 log response ratio (lnR) datasets obtained from 41 independent articles, we established that quinolones (QNs) significantly (p < 0.05) boost N2O emissions. Conversely, cycloheximide and aminoglycosides (ARs) demonstrated notable inhibitory effects. Antibiotic pollution at concentrations within 1 ppm significantly promoted soil N2O emissions, whereas pollution at concentrations exceeding 10 ppm significantly (95% CI > 0) inhibited N2O emissions. Subsequently, we investigated the changes in oxidation-related microorganisms (AOM), nitrite-oxidizing bacteria (NOB), comammox bacteria, denitrifying bacteria as well as dissimilatory nitrate reduction to ammonium (DNRA) and anammox processes under antibiotic stress. Antibiotics unequally affect microbial N2O production and consumption. Our findings offer valuable insights into the complex relationship between antibiotics and N2O emissions, contributing to a better understanding of the environmental consequences of antibiotic contamination in agricultural systems. [ABSTRACT FROM AUTHOR]

Abstract\nNOVELTY STATEMENTThe use of woody species for the remediation of heavy metal-contaminated soils is an environmentally friendly and economically viable strategy. This study investigates the phytoextraction abilities of 15 woody species for copper, lead and zinc in contaminated soil. The results indicated that all species showed phytoextraction ability, with metal concentrations varying from 5.59 to 27.45 mg·kg−1 for Cu, 2.79 to 16.75 mg·kg−1 for Pb and 22.13 to 185.72 mg·kg−1 for Zn in the stem tissues depending on the species. Pterocarya stenoptera, Paulownia fortunei and Salix matsudana were identified as the top performers in terms of overall phytoextraction capacity. Notably, their capacity to transport zinc exceeded that of copper and lead. The enrichment of copper, lead and zinc in the soil showed a synergistic effect in the presence of heavy metal. The distribution of heavy metals within plant tissues was affected by water content and the inherent toxicity of metals. The study highlights that the accumulation of tree biomass and water content in the stem play a significant role in determining the amount of heavy metals phytoextracted. This insight offers a quick method for the rapid selection of woody species for phytoremediation in urban soils contaminated with heavy metals.Dendroremediation is an important ecological remediation measure, and efficient selection strategies for woody species have become the key to the application of phytoremediation engineering. The extraction ability of 15 woody species for heavy metal and their correlation with wood characteristics were tested and analyzed by field trials. The study highlighted that the accumulation of tree biomass and water content in the stem play a significant role in determining the amount of heavy metals phytoextracted. This insight offers a quick method for selecting woody species for remediation in urban soils contaminated with heavy metals. [ABSTRACT FROM AUTHOR]

The excessive use of fungicides in agriculture causes challenges like pathogen resistance, soil and water contamination, and potential health risks. Sustainable options like Pseudomonas spp. and yeast are being explored as bioinoculants to promote plant growth and inhibit fungal proliferation. 87 isolates, comprising 36 fluorescent Pseudomonas spp. and 51 yeast isolates were obtained from healthy fruits and vegetables. Yeast (YFSL) and Pseudomonas (PFSL) isolates significantly (p < 0.05) inhibited the in-vitro growth of Fusarium solani and Drechslera sp. Experiments in a screen house for 90 days used a randomized block design to study the effects of bioinoculants on plant and fruit health. Moreover, plants and fruits treated with these bioinoculants showed increased levels of salicylic acid (66.14%), total phenolic content (59.67%), chlorophyll (24.31%), carbohydrates (40.38%), phosphorus (0.24%), and antioxidant activity (90%). The treatments displayed higher levels of plant defensive enzymes, chitinase (0.09 mg/h/protein) and β-1-3-glucanase (0.093 mg/h/protein). The increased concentrations of antioxidant enzymes like SOD (0.07 U/L), POD (0.23 U/L), and APX (0.24 U/L) were also observed in the fruits of bio-inoculated plants. However., the difference in results was non-significant (P ≤ 0.05). This study demonstrates the Efficacy of bioinoculants in improving plant growth, compositional characteristics, and antioxidant activities while reducing losses in tomato plants and fruits. [ABSTRACT FROM AUTHOR]

AbstractGlyphosate stands out in the eucalyptus management, which makes it essential to know its behavior, its effects on the plant, and possible environmental impacts. This study aimed to identify and quantify the root exudation of glyphosate and aminomethylphosphonic acid (AMPA) by Eucalyptus urophylla with chromatographic and biological methods. The five glyphosate doses were tested (0, 360, 720, 1080 and 1440 g a.e ha−1) on E. urophylla plants. The physiological and intoxication evaluations were performed after herbicide application. Water samples remaining from the pots were used for chemical quantification of root exudation of glyphosate and AMPA in high-performance liquid chromatography. Cucurbita pepo plants were used as bioindicators of glyphosate in the water remaining in the pots after applying herbicide. The increase in glyphosate doses promoted linear growth in E. urophylla intoxication and significantly reduced total dry mass and root production. E. urophylla plants had their photosynthetic, transpiratory, and stomatal conductance rates reduced as the herbicide doses increased. The AMPA root exudation was not detected, but it was possible to identify the presence of glyphosate by bioassay and chemical methods. Root exudation of glyphosate by eucalyptus can result in lesser herbicide action in plant control and cause contamination of deeper soil layers. [ABSTRACT FROM AUTHOR]

ABSTRACT The Oryctes rhinoceros (Scarabaeidae: Coleoptera) is a common coleopteran insect in tropical and subtropical areas with many potential uses. Its larvae are commonly found in dead coconut trees and hay piles in the wild and are widely distributed in the northern hemisphere. This study investigates the environmental factors influencing the growth of Oryctes rhinoceros beetle larvae and provides valuable insights into their breeding conditions versus their potential applications. The research examined three key affecting factors of larval development over time, namely, moisture content, growth space and soil content. Results of a pretest run revealed that moisture content, but not the soil content, affected the larval survival greatly. A reasonable confinement on feed moisture (i.e., 30%–60%) was included in the later conducted three‐factor factorial experiment. At last, results of the factorial run suggested that: (1) for a consistent and massive larval breeding, environmental factors, setting moisture content at 60%, larval space at 100 cm3/larva and no soil addition, are deemed appropriate, (2) for nutritional purpose, setting moisture content at 60%, larval space at 300 cm3/larva and no soil addition are recommended, and (3) for soil pollution remediation, setting moisture content at 60%, larval space at 100 cm3/larva and a soil‐to‐feed (S/F) ratio of 2:1 is concluded. This study marks the first engineering breeding exploration of Oryctes rhinoceros larvae, offering practical recommendations for various research purposes and applications. [ABSTRACT FROM AUTHOR]

Contamination of agricultural soil by heavy metals poses a significant threat to soil quality and crop yields. Using plants as a natural remediation approach attracts researchers' attention around the world. A 16-month pot experiment was conducted using Conocarpus erectus in a randomized complete block design. The growth, enzymatic activity, electrolyte leakage, and remediation potential were estimated under Cd nitrate]40 low (L), 60 medium (M), 80 high (H) mg/kg soil [and Pb nitrate]400 (L), 700 (M), 1,000 (H) mg/kg soil [applied individually and in combination. Conocarpus erectus demonstrated a good tolerance (over 70%) against lower and medium cadmium (Cd) and lead (Pb) levels and a medium resistance against high Cd and Pb levels, with a survival rate of 100% under all the treatments used. The most negative treatment on the growth traits and tolerance of C. erectus was (H) Cd and (H) Pb, which reduced plant height; chlorophyll index; dry weights of the leaves, stems, and roots; root length; and tolerance index of biomass and roots by 25.87%, 48.97%, 50.56%, 47.25%, 58.67%, 50.18%, 51.00%, and 50% in comparison to the respective control, consecutively. Relative to the control, all Cd and Pb applications increased polyphenol oxidase (PPO), peroxidase (POD), and catalase (CAT) activities, and the increment was parallel up to medium Cd and Pb levels and then decreased with their high levels but still higher than the control. Electrolyte leakage (EL) was upheaved by raising the levels of Cd and Pb, and it reached the maximum (52.79%) at the (H) Cd (H) Pb treatment. Cd and Pb in the leaves, stems, and roots were boosted by raising their levels in the treatments. Conocarpus erectus is considered a phytoextractor for the Cd levels used because the bioconcentration factor of the stem (BCFs) and the translocation factor (TF) of Cd were >1, and it is a suitable plant for Pb phytoextraction at (L) Pb, (M) Pb, and (M) Cd (M) Pb levels because its Pb BCFs and bioconcentration factor of the root (BCFr) were <1 and its Pb TF was >1. On the other hand, C. erectus is considered a phytostabilizator for Pb at (H) Pb, (L) Cd, (L) Pb, and (H) Cd (H) Pb levels because its Pb BCFs, BCFr, and TF were <1. [ABSTRACT FROM AUTHOR]

Rotational shifting cultivation (RSC) is commonly practiced in northern Thailand for upland rice cultivation, primarily for household consumption. However, the potential health risks from heavy metal contamination in these soils have not been thoroughly explored. This study aimed to evaluate the contamination of six heavy metals (Arsenic (As), Mercury (Hg), Cadmium (Cd), Lead (Pb), Copper (Cu), and Chromium (Cr)) in upland rice across RSC fields with varying fallow periods and assess the associated health risks from rice consumption. Four RSC fields with 5, 6, 10, and 12-year fallow periods were examined. The RSC-6Y and RSC-12Y fields were used for upland rice cultivation in 2022, while the RSC-5Y and RSC-10Y fields were cultivated in 2023. The geo-accumulation index (Igeo) was calculated, and translocation factors (TF) were assessed for the transfer of heavy metals from soil to straw (TFStraw/Soil), straw to grain (TFGrain/Straw), and soil to grain (TFGrain/Soil). The results indicated that after burning vegetation in the RSC fields, the highest concentrations of Pb, Cr, and Hg were found in the ash. In RSC soils, Cu, Cr, As, Pb, and Hg levels were below reference standards, with Cd undetected. In rice grains, the order of concentration was Pb > Cu > Cr > As, with Hg and Cd undetected. Pb levels in rice grains exceeded the safety threshold. Igeo values indicated no contamination to moderate contamination across sites, with negative Igeo values for Cr and Cu, and zero values for Cd. The TF results showed limited transfer of As, Hg, and Cd from soil to rice plants (TFStraw/Soil < 0.1), but notable transfer for Pb, Cr, and Cu. Pb was readily transferred from soil to grain (TFGrain/Soil), posing a potential health risk. The study highlights potential non-carcinogenic and carcinogenic risks from heavy metal exposure, particularly Pb, and underscores the need for further research to determine contamination sources and mitigation strategies. [ABSTRACT FROM AUTHOR]

Heavy metals (HMs) contamination has gained much attention due to its high degree of toxicity for living organisms. Therefore, different techniques are underway to eradicate HMs from the environment. Among the biological techniques, phytoremediation is a suitable method, but owing to the slow rate and chance of HMs penetration into the food chain, alternative techniques are needed to reduce their phytotoxicity, and biochar is one of them. Due to the diverse characteristics, biochar immobilizes HMs in the soil by improving soil pH, ion exchange, electrostatic interactions, complexation, precipitation, surface adsorption, and microbial activation. Thereby, amendment of biochar in the HMs-contaminated soils reduces HMs toxicity to plants and limits their penetration into the food chain. In contrast, some biochars have also been studied to induce metal availability in soils and subsequently its uptake by plants. This dual role of biochar depends on the feedstock of biochar, incineration temperature, and the rate of application. Moreover, biochar treatments enhance plant growth under HMs stress by improving nutrient availability, water retention capacity, scavenging of reactive oxygen species, and photosynthetic efficiency. Owing to the beneficial characteristics of biochar in HMs-contaminated sites, the number of publications has tremendously increased. Additionally, the plant species and the types of HMs that have been tested frequently under biochar treatments in these articles have been studied. Overall, the current study would help in understanding the mechanisms of how biochar influences phytoremediation of HMs and improves plant growth in HMs-polluted soils and the current scenario of the available literature. [ABSTRACT FROM AUTHOR]

ABSTRACT Cadmium (Cd) contamination in agricultural soil brings severe health risks through the dietary intake of Cd‐polluted crops. The comprehensive role of pectin in lowering Cd accumulation is investigated through low Cd accumulated (L) and high Cd accumulated (H) cultivars of L. sativa. The significantly different Cd contents in the edible parts of two L. sativa cultivars are accomplished by different Cd transportations. The pectin is the dominant responsive cell wall component according to significantly increased uronic acid contents and the differential Cd absorption between unmodified and modified cell wall. The chemical structure characterization revealed the decreased methyl esterification in pectin under Cd treatment compared with control. Significantly brighter LM19 relative fluorescence density and 40.82% decreased methanol in the root pectin of L cultivar under Cd treatment (p < 0.05) supported that the de‐methyl esterification of root pectin is more significant in L cultivar than in H cultivar. The pectin de‐methyl esterification of L cultivar is achieved by the upregulation of pectin esterases and the downregulation of pectin esterase inhibitors under Cd treatments, which has facilitated the higher Cd‐binding of pectin. Our findings provide deep insight into the differential Cd accumulation of L. sativa cultivars and contribute to the understanding the pollutant behaviors in plants. [ABSTRACT FROM AUTHOR]

Marine plastic pollution has become a major concern as it threatens marine life and human health. Most of the plastic that enters the ocean is either consumed by animals and/or trapped in sediments. However, there is little information on how sediment properties might be affected. In this article, we explore the impact of microplastic inclusions in marine settings by using PVC plastic chips and two soil samples as analogues. We conducted a comprehensive experimental study to investigate changes in compressibility, strength, stiffness, thermal and hydraulic conductivity, and particle migration by varying plastic content. Results show that as low as 1% of plastic content by volume can lead to irreversible consequences in sediment behavior while coarse particles display a heightened sensitivity than pure fines. As plastic content in sediment increases year-by-year, we anticipate significant repercussions in marine life, the future landscape of the seafloor and subsurface phenomena. [ABSTRACT FROM AUTHOR]

The increasing levels of cadmium (Cd) pollution in agricultural soil reduces plant growth and yield. This study aims to determine the impact of green synthesized zinc oxide nanoparticles (ZnO-NPs) on the physiochemical activities, nutrition, growth, and yield of Zea mays L. under Cd stress conditions. For this purpose, ZnO-NPs (450 ppm and 600 ppm) synthesized from Syzygium aromaticum were applied through foliar spray to Z. mays and also used as seed priming agents. A significant decline in plant height (35.24%), biomass production (43.86%), mineral content, gas exchange attributes, and yield (37.62%) was observed in Cd-spiked plants compared to the control. While, 450 ppm ZnO-NPs primed seed increased plant height (18.46%), total chlorophyll (80.07%), improved ascorbic acid (25.10%), DPPH activity (26.66%), and soil mineral uptake (Mg+2 (38.86%), K+ (27.83%), and Zn+2 (43.68%) as compared to plants only spiked with Cd. On the contrary, the foliar-applied 450 ppm ZnO-NPs increased plant height (8.22%), total chlorophyll content (73.59%), ascorbic acid (21.39%), and DPPH activity (17.61%) and yield parameters; cob diameter (19.45%), and kernels numbers 6.35% enhanced compared to plants that were spiked only with Cd. The findings of the current study pave the way for safer and more cost-effective crop production in Cd-stressed soils by using green synthesized NPs and provide deep insights into the underlying mechanisms of NPs treatment at the molecular level to provide compelling evidence for the use of NPs in improving plant growth and yield. NOVELTY STATEMENT: Novelty statement: Phyto zinc nanoparticles improve stress tolerance and growth of Zea mays under cadmium stress [ABSTRACT FROM AUTHOR]

This study aimed to examine the potential of soil amendment-assisted phytoremediation using ryegrass in reclaiming abandoned gold mine soil in southwestern Ghana, with a specific focus on the soil contamination hazards associated with metals and metalloids. A pot experiment lasting 60 days was carried out to assess the efficacy of soil amendments, such as compost, iron oxide, and poultry manure, in mitigating environmental hazards. Three soil contamination indices (soil contamination = CF, enrichment factor = ER, and pollution load index = PLI) were used to calculate the extent of soil contamination, enrichment, and pollution of the sites with Co, Hg, Ni, Mo, Se, Sb, and Pb. The findings show that Hg made the greatest contribution (with a maximum soil CF of 18.0) to the overall PLI, with a maximum value of 74.4. The sites were averagely and consequently enriched with toxic elements in the decreasing order: Ni (ER = 33.3) > Mo (20.5) > Sb (14.1) > Pb (11.0) > Hg (7.9) > Se (2.1). The bioaccumulation factor (BCF > 1) suggests that ryegrass has the ability to phytostabilize Co, Hg, Mo, and Ni. This means that the plant may store these elements in its roots, potentially decreasing their negative effects on the environment and human health. Ultimately, the addition of combined manure with iron oxides might have augmented the sequestration of these metals in the root. The elements may have accumulated through sorption on manure or Fe surfaces, dissolution from watering the plants in the pot, or mineralization of organic manure. Thus, ryegrass has shown potential for phytostabilisation of Co, Hg, Mo, and Ni when assisted with a combination of manure and iron oxides; and can consequently mitigate the environmental and human health impacts. NOVELTY OF WORK: Gold mining in Ghana has caused significant environmental damage and political unrest. Research on environmentally friendly solutions to land degradation is crucial for restoring degraded lands, preserving ecosystem integrity, restoring livelihoods, and protecting public health in gold mining hotspots. However, previous studies have often overemphasized the use of trees in improving soil quality. Other past studies have merely collected plant species for heavy metal analysis without concrete pots or field experiments. Ryegrass has only been limited to arsenic remediation, and its phytoremediation ability for other toxic elements like Co, Hg, Mo, Ni, Pb, Sb, and Se has not been investigated. This work reports for the first time the phytostabilisation ability of ryegrass for potentially toxic elements in a Ghanaian context. Consequently, recommendations are made for reclaiming gold-mine-affected sites while at the same time providing evidence for widening the choice of plant species available for restoring mine-derelict lands. Ultimately, the study fills the gap in phytoremediation research within the global scientific community and Ghana in particular. [ABSTRACT FROM AUTHOR]

ABSTRACT The increasing contamination of agricultural soils with cadmium (Cd) poses a significant threat to human health and global food security. Plants initiate a series of mechanisms to reduce Cd toxicity. However, the response of maize to Cd toxicity remains poorly understood. In this study, we identified that ZmHMT3, which encodes a homocysteine S‐methyltransferases family protein, acted as a regulator of Cd tolerance in maize. Subcellular localization and in situ PCR exhibited that ZmHMT3 was localized in the cytoplasm and predominantly expressed in the phloem. Overexpression of ZmHMT3 enhanced Cd tolerance and reduced Cd concentration in both shoots and roots. In contrast, ZmHMT3 mutants attenuated Cd tolerance but did not change shoot Cd concentration. Heterologous overexpression of ZmHMT3 in rice enhanced Cd tolerance and reduced grain Cd concentration. Transcriptome analysis revealed that ZmHMT3 upregulated the expression of stress‐responsive genes, especially glutathione S‐transferases (GSTs) and transcription factors, including MYBs, NACs and WRKYs, and modulates the expression of different ATP‐binding cassette (ABC) transporters, thereby enhancing Cd tolerance. Collectively, these findings highlight the pivotal role of ZmHMT3 in Cd tolerance and as a candidate gene for improving Cd tolerance in elite maize varieties. [ABSTRACT FROM AUTHOR]

Anaerobic digestion and composting of biowastes are vital pathways to recycle carbon and nutrients for agriculture. However, plastic contamination of soil amendments and fertilizers made from biowastes is a relevant source of (micro‐) plastics in (agricultural) ecosystems. To avoid this contamination, plastic containing biowastes could be pyrolyzed to eliminate the plastic, recycle most of the nutrients, and create carbon sinks when the resulting biochar is applied to soil. Literature suggests plastic elimination mainly by devolatilization at co‐pyrolysis temperatures of > 520°C. However, it is uncertain if the presence of plastic during biomass pyrolysis induces the formation of organic contaminants or has any other adverse effects on biochar properties. Here, we produced biochar from wood residues (WR) obtained from sieving of biowaste derived digestate. The plastic content was artificially enriched to 10%, and this mixture was pyrolyzed at 450°C and 600°C. Beech wood (BW) chips and the purified, that is, (macro‐) plastic‐free WR served as controls. All biochars produced were below limit values of the European Biochar Certificate (EBC) regarding trace element content and organic contaminants. Under study conditions, pyrolysis of biowaste, even when contaminated with plastic, can produce a biochar suitable for agricultural use. However, thermogravimetric and nuclear magnetic resonance spectroscopic analysis of the WR + 10% plastics biochar suggested the presence of plastic residues at pyrolysis temperatures of 450°C. More research is needed to define minimum requirements for the pyrolysis of plastic containing biowaste and to cope with the automated identification and determination of plastic types in biowaste at large scales. [ABSTRACT FROM AUTHOR]

This paper demonstrates the characteristics of soil-like material extracted from the landfill mining activity at the Ariyamangalam dump yard, located in Tiruchirappalli city of southern India. The landfill mining waste was collected and characterised for contaminant potential, thereby its suitability for reuse applications offsite. Soil-like materials of size fractions finer than 2 mm have been assessed for their physico-chemical characteristics and compared the acceptability criterion with the drinking standard IS 10500: 2012. Total soluble solids and closely associated parameters have been determined in the water extract from soil-like materials and local soils and compared with the international regulatory standards for reuse acceptability. From the total heavy metal concentration of soil-like material and local soil, three different pollution indices, namely contamination ratio, geo-accumulation index, and enrichment factor, have been identified and categorised soil-like material as low contaminated for lead; low to moderately contaminated for chromium, nickel, and iron; moderately contaminated for manganese; and moderately to strongly contaminated for copper and zinc. The organic and moisture content of soil-like material was reported as 22 and 19.6%, whereas the local soil showed 2.4 and 1.5%, respectively. Due to its enormous organic content, soil-like materials pose as less efficient in utilising offsite applications without primary treatment. [ABSTRACT FROM AUTHOR]

Nicosulfuron residues in soil can be harmful to the environment. In this study, Klebsiella oxytoca ES5 and Klebsiella grimontii ES8 were isolated to construct the ES58 bacterial complex. The culture medium was optimized using response surface methodology, nicosulfuron degradation by ES58 reached 97.21 % in 96 h. The optimal degradation conditions were: temperature: 25℃, pH 6, initial nicosulfuron concentration: 50 mg L−1 and inoculum volume: 2 %. The two individual strains and the bacterial complex were tested for the ability of nitrogen fixation, phosphorus solubilization, potassium decomposition and iron carrier production. The results revealed that both strains and the bacterial complex had the ability to promote the growth, with bacterial complex being more capable than the two individual bacterial strains. After 28 d of bioremediation of nicosulfuron-contaminated soil by ES58, degradation rate of nicosulfuron was 90.84 % in the unsterilized soil. Furthermore, the remediation process restored the activities of catalase, invertase, dehydrogenase and urease in the soil. The ES5-specific gene budA and ES8-specific gene ldh were detected in the soil at the 28th day. ES58 exhibited different effects on the growth indexes of nicosulfuron-sensitive crops. The study provides a novel strategy for nicosulfuron degradation effective by constructing and utilizing bacterial complex. [Display omitted] • Two strains of nicosulfuron efficient degrading bacteria were isolated and identified. • The degradation characteristics of the complex bacterium ES58 were investigated. • The growth-promoting ability of the composite bacterium ES58 was determined. • Bioremediation of nicosulfuron contaminated soil by the complex bacterium ES58 was studied. [ABSTRACT FROM AUTHOR]

Quantifying the root uptake of hydrophobic organic contaminants (HOCs) by plants remains challenging due to the lack of data on the freely available fractions of HOCs in soil porewater. We therefore hypothesized that a passive sampler could act as a useful tool to evaluate the root uptake potential and pathways of HOCs by plants in soil. We tested this hypothesis by exploring the uptake of polybrominated diphenyl ethers (PBDEs) and organophosphate esters (OPEs) by carrot and lettuce with the codeployment of passive samplers in a contaminated soil system. The results showed that the amounts of PBDEs enriched in carrot and lettuce were positively correlated with those in a passive sampler (r2 = 0.46–0.88). No concentration correlation was observed for OPEs between lettuce and passive samplers, due to possible degradation of OPEs in lettuce. The root‐to‐porewater ratios of PBDEs and OPEs, respectively, were 6.2 to 11 and 0.05 to 0.88 L g−1 for carrot, and 8.8 to 130 and less than reporting limits to 1.2 L g−1 for lettuce. The ratios were negatively correlated with log KOW values for carrot, but increased with increasing log KOW values over a range of 1.97 to 6.80, and then decreased with log KOW values greater than 6.80 for lettuce. This finding indicated that passive transport and partition were the accumulation pathways of PBDEs and OPEs in carrot and lettuce, respectively. Overall, passive samplers performed adequately in assessing the available fractions of persistent HOCs in plants, and can serve as a viable tool for exploring the pathways for plant root uptake of HOCs. Environ Toxicol Chem 2024;43:2338–2349. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Contamination of soils with heavy metals (HMs) is a serious concern due to the non-biodegradability and accumulation of these metals in living organism. The aim of this study was to evaluate the effectiveness of fish scale powder, chitin, and chitosan in reducing zinc (Zn) accumulation of quinoa grown on Zn-polluted soil. A 3*4 factorial greenhouse trial was conducted with three levels of Zn contamination (0, 100, and 200 mg kg−1) and four types of amendment (control, and 0.15% of each fish scale powder, chitin, and chitosan). The quinoa seeds were sown in soil treated with Zn contamination and amendments. Results showed that application of amendments especially chitosan increased shoot and root dry weight and greenness index of quinoa leaf. While high soil Zn levels decreased cationic micronutrients uptake in quinoa shoot, chitosan addition desirably enhanced cationic micronutrients uptake in quinoa shoot. Overall, amendment addition significantly decreased Zn concentration and uptake in plant; the highest decrease was observed following the application of chitosan. Although the application of high Zn levels significantly increased the values of phytoextraction efficiency, application of chitin and chitosan significantly decreased it. The value of translocation factor was lower than one, demonstrating that a large amount of Zn was stabilized in the root tissues, while a small amount of this metal was transferred to aboveground parts of quinoa. Results of this study revealed that fish scales derivatives were effective in preventing Zn toxicity and at the same time increasing cationic micronutrients contents of quinoa grown on HMs-polluted soil. [ABSTRACT FROM AUTHOR]

Broad-spectrum veterinary antibiotic tylosin (TYL) is utilized in livestock and poultry. Due of its extensive usage and animal excretion in urine and feces, it affects the environment and human health. For determining the equilibrium time, the adsorption maximum capacity and the optimal isotherm model, adsorption batch tests have been conducted. Sips and Pseudo-second order models had R2 values of 0.9937 and 0.9764, respectively, and best matched experimental isotherm and kinetic data. The maximum TYL uptake onto soil was 2355.08 mg.kg−1. Using fixed bed adsorption experiments, the current study clarifies the issue of soil contamination in conditions that are close to natural phenomena. Fixed bed adsorption tests demonstrated that the inlet TYL concentration, soil bed height, and flow rate, influenced saturation and breakthrough times. Bohart-Adams, Thomas, and Yoon-Nelson models matched the experimental findings well in a variety of conditions. With 100 mg.L−1 concentration, 4 cm bed height, and 5 mL.min−1 flow rate, the maximal bed capacity of 1277.06 mg.kg−1 was achieved with R2 value of 0.9797. Experimental findings also indicated that the adsorption capacity in batch and dynamic tests are of the same range of magnitude. Based on this, tylosin is a probable soil contaminant. [ABSTRACT FROM AUTHOR]

Heavy metal accumulation in soil can seriously harm human health, and it is necessary to identify the accumulation status and access the potential risks for local pollution control and sustainable economic development. This study evaluated the pollution level, spatial distribution, potential risk and sources of soil heavy metals along the Zhengzhou-Kaifeng intercity railway and compared pollution characteristics in north side soils with south side soils of the railway. A total of 260 soil samples were collected from a section along the railway. In practice, only the average Zn and Pb contents in soils were slightly higher than their corresponding risk screening values. The heavy metal enrichment in the north side soils was marginally lower than that in the south side soils. The spatial distribution of soil heavy metals except Pb could be mainly influenced by the different land use types. The geoaccumulation index and potential ecological risk of a single heavy metal indicated that Cd was the major contaminant with moderate pollution and high ecological risks in the south side soils and none to moderate pollution and moderate ecological risks in the north side soils. However, the mean multimetal potential ecological risk values suggested that the north side soils were at low ecological risks and the south side soils were at moderate ecological risks. The comprehensive non-carcinogenic risks and total carcinogenic risks for adults were low and acceptable, respectively. Pearson correlation analysis, PCA, and APCS-MLR analyses identified that the contributions of natural sources, mixed sources of industrial and traffic activities, agricultural activities, and other sources were 57.49%, 21.44%, 12.67% and 8.40%, respectively, and the major soil pollution Cd was mainly related to mixed sources of industrial and traffic activities. Therefore, continuous soil heavy metal monitoring is essential to elucidate the long-term railway operation effect on soil heavy metal accumulation. [ABSTRACT FROM AUTHOR]

Contamination at shooting ranges is a growing concern due to the accumulation of potentially toxic elements in the soil. The aim of the study was to determine the level of soil contamination in different types of Lithuanian shooting ranges (clay-target, practical, small-bore) and assess the potential ecological risks. Soil samples were taken in two soil layer depths (0–10 cm and 10–30 cm) and locations (range floor and berm/target line) of different types of shooting ranges. The soils of the practical and small-bore shooting ranges were neutral, clay target – slightly alkaline. The soil of the clay-target firing range floor had a significantly lower organic matter, than small-bore and practical firing ranges. Lead contamination was significantly higher in the floor and berm surface soil and subsoil (about 1000 mg kg−1 and 360–527 mg kg−1, respectively) of the practice range compared to the others and controls. The Cd concentrations in the surface soil of the practical range and the small-bore firing ranges and in the soil of the berm were considerably higher than in the soil of the clay target. There was a significant negative correlation between soil pH and Pb and Cd concentrations. Pb content was positively correlated with organic matter content. The soils of the practical range floor and berm indicated high ecological risk. The research showed that heavy metal contamination is specific in different types of shooting ranges, therefore various management practices should be applied to prevent pollution in particular shooting range. [ABSTRACT FROM AUTHOR]

Silkworm excrement (SE) and silkworm excrement-derived biochar (BC) were applied to atrazine-contaminated soil at the rates of 0% and 0.5% (w/w), respectively. The effect of organic amendments on sorption capacity, microbial biomass carbon, enzyme activity (dehydrogenase, urease and catalase) and bacterial composition in soil were evaluated. Atrazine significantly decreased the microbial activity and diversity in soil. Both SE and BC treatments increased the sorption of atrazine in soil. SE treatment significantly increased the microbial biomass carbon and enzyme activity in contaminated soil. Unlike the addition of silkworm excrement, BC treatment had no significant effect on dehydrogenase activity. Additionally, Illumina-MiSeq sequencing analyses showed that the two organic amendments increased the Shannon index of bacteria. SE treatment improved the relative abundance of Bacteroidetes. BC treatment improved the Proteobacteria in atrazine contaminated soil. [ABSTRACT FROM AUTHOR]

Efficient control of heavy metal pollution necessitates a comprehensive understanding of pollutant sources. In this study, we conducted a thorough investigation of 11 metals in the soil of an electronic waste (e-waste) recycling facility in South China. The sources of these metals were determined through a combination of statistical analysis and the UNMIX model. Despite government intervention, our findings reveal significant pollution of nickel, copper, zinc, cadmium, and lead in the study area. Primary contributors to heavy metal contamination in the soil were identified as demolition activities, transport emissions, and atmospheric deposition. Utilizing a source risk assessment model, we observed that children face higher noncarcinogenic and carcinogenic risks compared to adults. Remarkably, the total hazard index of the study area was found to be considerably lower than that of other e-waste dismantling cities. Moreover, the total carcinogenic risk was noted to be one order of magnitude lower than both other e-waste dismantling cities and industrial and mining cities. While acknowledging the government's commendable achievements in the standardized management of e-waste dismantling activities, our study underscores the need for targeted measures to further reduce pollution and safeguard the health of residents. These results emphasize the importance of ongoing efforts to enhance environmental protection strategies and underscore the significance of tailored interventions for sustainable pollution control in e-waste recycling facilities. [ABSTRACT FROM AUTHOR]

The presence of oil contamination causes changes in mechanical properties of clayey soil trenches with low liquid limits (CL) such as stress-strain behavior, rupture plain position, plastic zone, and strain energy for soil trenches compared with uncontaminated soils. These changes usually lead to a lower factor of safety against failure and expansion of the plastic zone. The effects of crude oil contamination on the soil shear strength were evaluated by direct shear and plate load tests for various clays and sandy soils. In this research, a numerical finite element modeling in ABAQUS software was used to estimate the effect of oil contamination in the range of 0 to 16% (0%–4%–8%–12%–16%) on the stability safety factor of vertical clayey trenches with heights of 3 m, 4 m, 5 m, and 6 m, and the results were compared with results of a limit state analysis. The findings of the limit equilibrium method show that adding 4% of oil contamination to a clayey trench will decrease 62% of its critical depth. Also, the numerical analysis results show that adding oil contamination in the range of 0 to 16% to the clayey soil will increase the maximum displacements of the trenches to five times their clean state. [ABSTRACT FROM AUTHOR]

The problem of soil heavy metal pollution in decommissioned sites has become an environmental threat and challenge faced by countries around the world. Establishing a high-precision 3D model of contaminants is essential for pollution risk assessment and accurate monitoring of contaminated sites. In this study, 3D geological model and SSA-XGBoost model are proposed to predict heavy metal concentration in a site. These models can effectively improve the prediction accuracy of soil heavy metals, and the RMSE of the XGBoost model optimized by the SSA algorithm is reduced by 24.3%-34.3%. Compared with other machine learning models, the SSA-XGBoost model has optimal performance in improving the prediction accuracy of soil heavy metals. It is suitable for the areas with significant spatial heterogeneity of soil heavy metals. Using the SSA-XGBoost model and 3D geological model, the 3D spatial distribution characteristics of heavy metals in contaminated soil are determined. The concentration of soil pollutants ranked as As>Pb>Mo, and the overall pollution degree decreases gradually from top to bottom. The pollutants are mainly distributed in the production workshop area in the southwest of the site, and the miscellaneous fill layer is the main soil layer that needs to be remediated. [ABSTRACT FROM AUTHOR]

Presence of cadmium in soil affects the growth status of plants; research on the underlying mechanism has focused on its lethal and sublethal consequences in plants, ignoring the impacts of soil organisms. Therefore, this study designed a microorganism – earthworm – plant ecosystem, investigated the influence of Cd (0, 0.3, 1.0, and 3.0 mg kg−1) on the growth of Arabidopsis thaliana in the presence of earthworms (Eisenia fetida), and revealed the mechanisms from the perspective of altered relationships among different soil organisms. In this study, there was no significant difference in the death rate of earthworms with low Cd addition concentration, but the microorganisms in earthworms and soil microorganisms changed, abundance of Actinomycetes in soil increased, while Planctomycetes decreased, Mycobacterium in the gut of Eisenia fetida decreased under Cd stress. Microorganisms affect soil pH, which in turn affects soil physicochemical properties and the form of cadmium in soil. Compared with the control, soil pH significantly decreases under cadmium stress, Under 0.3 mg kg−1 treatment, soil total nitrogen, available phosphorus and total potassium are 181.11, 5.09, 51.90, and 7.55 mg kg−1, respectively, They were significantly higher than control group. Improved the growth environment of Arabidopsis thaliana and promoted the absorption of Cd in soil which affected the proportion of available Cd in the soil (when Cd was added at 1.0 mg kg−1, the proportion of available Cd in the soil decreased significantly from 95.05% to 49.40%). A. thaliana also absorbed more Cd, which increased Cd toxicity, and the reproductive growth of A. thaliana was enhanced, while vegetative growth was weakened.Compared with the control group (278.11 mg), the biomass of A. thaliana decreased significantly to 189.83 mg when Cd was supplemented at 0.3 mg kg−1. Therefore, the activities of and interactions among earthworms, plants, and microorganisms play important roles in reducing soil heavy metals and improving soil properties. HIGHLIGHTS: Under cadmium (Cd) stress, the relative abundance of Actinomycetes in soil increased, while Planctomycetes decreased. The relative abundance of Mycobacterium in the gut of Eisenia fetida decreased under Cd stress. Microbial changes and E. fetida activity changed soil physical and chemical properties and reduced the ratio of soil available Cd. Microorganisms and E. fetida enhanced the reproductive growth and weakened the vegetative growth of Arabidopsis thaliana. [ABSTRACT FROM AUTHOR]

Phytotoxic effects of herbicides have been reported on non-target plant species. This study was performed to investigate the growth of Napier grass cv. Pak Chong 1 in herbicide atrazine-contaminated soil; the effect of 1-naphthalene acetic acid, 6-benzyladenine and thidiazuron to stimulate the growth of grass grown in atrazine-contaminated soil; and to determine the remaining atrazine in the soil. The experiment was performed in a factorial completely randomized design with 2 × 10 factors. The first factor was atrazine concentration and the second factor was the application of plant growth regulator. The growth of the plants and atrazine remaining in the soil was analyzed at the end of the experiment (after 26 days). The results showed that Napier grass cv. Pak Chong 1 was tolerant to 6.8 mg/kg atrazine contamination in soil. The shoot growth and root growth of grass grown in atrazine-contaminated soil did not significantly differ from that grown in non-contaminated soil. Thidiazuron and 6-benzyladenine at 0.1 mg/l tended to increase the shoot dry weight of the grass grown in both atrazine-contaminated and non-contaminated soil. Additionally, 10 mg/l of thidiazuron and 1-naphthalene acetic acid tended to decrease the shoot growth of grass grown in both contaminated and non-contaminated soil. Moreover, decreases in atrazine were detected in soil planted with Napier grass cv. Pak Chong 1 by about 67.65% within 26 days. [ABSTRACT FROM AUTHOR]

The presence of cyanide compounds in soil can lead to the formation and evaporation of hydrogen cyanide (HCN), while some of these compounds can undergo conversion by microorganisms present in the soil. However, high concentrations of cyanide can be toxic to soil microorganisms. During the gold extraction of mines, sodium cyanide (NaCN) solution is commonly used which results in a significant amount of cyanide waste that is regarded as an environmental pollutant. Previous studies have proposed physical, chemical, and biological methods to eliminate cyanide, but they have not achieved optimal efficiency. Unfortunately, the potential of artificial intelligence (AI) in this domain has been overlooked. Artificial Neural Network (ANN) models, specifically the multilayer perceptron (MLP) and simple linear regression, can significantly enhance and expedite the cyanide remediation process due to their remarkable predictive capabilities. In this study, an MLP and simple linear regression were employed to predict the biodegradation procedures of cyanide in soil. The study focused on cyanide waste generated by gold extraction factories and utilized environmental factors such as initial waste cyanide concentration, pH, soil and environmental temperature, humidity, chloride concentration, alkaline, electrical conductivity, precipitation, evaporation intensity, cyanide concentration, and initial pH as input data for the artificial neural network. The results of the MLP model revealed that electrical conductivity is the most influential factor in predicting the cyanide rate and initial pH of the waste soil. Conversely, the results of the simple linear regression indicated that the variables with the greatest impact on cyanide concentration are electrical conductivity (0.881), time (0.862), and alkalinity (0.724). By leveraging AI techniques such as ANN, this study demonstrates the potential for improved cyanide remediation. The integration of environmental factors and predictive models can contribute to more effective strategies for addressing cyanide pollution in soil. [ABSTRACT FROM AUTHOR]

In this study, pollution level, distribution, toxicity, molecular composition, probable sources as well as health risks of polycyclic aromatic hydrocarbons (PAHs) in urban and industrial soils of Kerman metropolis were investigated. Kerman is a fast-growing city and a fine example of an arid city in a developing country. For this purpose, concentrations of 16 individual PAHs in 30 samples taken from the city soils and its industrial zones were determined by gas chromatography/mass spectrometry. The ∑PAHs concentration in urban soil samples varied from 26.1 to 902.8 μg/kg, with the mean and median of 302.6 and 148.4 µg/kg, respectively. In comparison, ∑PAHs in industrial soils ranged from 26.8to 251.9 μg/kg, with the mean and median values of 65.9 and 42.9 µg/kg, respectively. Four-ring PAHs comprise the dominant compounds in urban soils, whereas, two- and three-ring PAHs proved to be the most abundant compounds in industrial soils. Source apportionment was conducted using ring classification, diagnostic ratios, PCA, and multilinear regression (MLR). Also, human health risk assessment was undertaken through employing US EPA standard statistical models. This survey revealed that PAH pollution in urban soils originates mainly from fossil fuel combustion and in industrial soils from petrogenic sources. On the whole, in the Kerman environment, the shares of petroleum combustion, natural gas combustion, and petrogenic sources were 45.32%, 34%, and 20.68% respectively. Based on this study, the ecological risk of PAHs was low-to-moderate, and incremental lifetime cancer risk for children and adults were 1.35 × 10−4 and 1.04 × 10−4 respectively, indicating rather high risks. [ABSTRACT FROM AUTHOR]

Anthropogenic activities release potentially toxic elements into the environment, which contaminate the food chain. The main objective of this research was to analyze the concentrations of As, Cd, Cr, Hg, and Pb in rice grains and soils, establish their correlation and transfer factors between soil and rice grains as well as evaluate their human health risk from consumption of rice cultivated in the Asante Akim area. The levels of As, Cd, Cr, Hg, and Pb in soil and rice samples were assayed using an Agilent 7700 Series inductively coupled plasma-mass spectrophotometer. The mean heavy metal content in soil was 7.5, 0.52, 0.47, 1.30, and 8.69 mg/kg for As, Cd, Cr, Hg, and Pb, respectively. Mean levels of the potentially toxic elements in rice were 0.082, 0.27, 0.48, 0.028, and 0.14 mg/kg for As, Cd, Cr, Hg, and Pb, respectively. Soil pollution indices showed that the soils were unpolluted with the potentially toxic elements studied. The concentrations of the potentially toxic elements in rice were below the maximum allowable concentration (MAC) recommended by the Codex Alimentary Commission except Cd which was marginally higher than the MAC. Dietary exposure to the elements to consumers was assessed by comparing the estimated daily intake (EDI) to the provisional tolerable daily intake (PTDI). The estimated daily intake values for As, Cd, Cr, Hg, and Pb were 1.45 × 10−4, 4.8 × 10−4, 8.5 × 10−4, 4.95 × 10−5, and 2.4 × 10−4, respectively. The HQ for all the potentially toxic elements was less than the permissible value of 1, suggesting that the consumption of rice from the study area constitutes no potential non-carcinogenic health risk to the population. This study is unique because the risk is evaluated from rice that is directly consumed, and this gives a clearer picture of the risk to humans. Regular monitoring studies should be conducted to ascertain the levels of heavy metals in rice cultivated in the area since heavy metals can accumulate and the concentrations could increase to toxic levels with time. [ABSTRACT FROM AUTHOR]

A study was conducted to determine the concentration of toxic heavy metals in various agrochemicals available in Bangladesh and to assess the burden of these metals on agricultural soils. An atomic absorption spectrophotometer (AAS) was used to measure the content of 4 toxic metals (Cd, Pb, Cr, and Ni) in the aqueous extract of various agrochemicals. There were significant differences in the amounts of Cd, Pb, Cr, and Ni in different brands of insecticides (mean < 0.01, 3.16, 17.32, and 47.33 µgg−1), fungicides (mean 12.42, 10.19, 9.63, and 243.34 µgg−1), phosphatic fertilizers (mean 25.43, < 0.01, 206.33, and 210.69 µgg−1), micronutrient fertilizers (mean 0.68, < 0.01, 43.43, and 65.79 µgg−1), and plant hormones (mean < 0.01, < 0.01, 9.90, and 43.08 µgg−1). The concentrations of Cd and Ni were on an average higher in phosphatic fertilizers, which exceeded the maximum acceptable limit of fertilizers in Bangladesh by 2.5 and 4.2 times, respectively. The study also revealed that the burden of toxic heavy metals from agrochemicals on farm soils was in the following order: phosphatic fertilizers > fungicides > micronutrient fertilizers > plant hormones > insecticides. Among the toxic heavy metals, Ni posed the highest burden on Bangladeshi farm soils due to a single application of different agrochemicals in a year. The average total burden of each metal in the soils of Bangladesh showed a decreasing trend in the order of Ni > Cr > Cd > Pb, resulting in a total metal burden of 22.88 g year−1 ha−1. Finally, the study recommended that certification about the content of metals be made mandatory for agrochemical manufacturing firms to ensure that their products entering in Bangladeshi markets are free from toxic metals. [ABSTRACT FROM AUTHOR]

The biological removal of a mixture of soil contaminants, namely, hydrocarbons, is not equally efficient for each compound. Some pollutants can be metabolized by the microbial consortium but also generated again as by-products from the removal of others. At the end of the runs, notwithstanding the high integral removal, single compounds can still be present with a relevant concentration. This paper presents the results achieved in a study of the aerobic degradation of diesel oil in three mesocosms carried out for several months with the same operative conditions. They differed in biological management: Natural Attenuation (NA), Biostimulated without inoculation (BS), and Biostimulated with Inoculation (BS + IN). At the end of the runs, the pollution removal was calculated by measuring the residual diesel oil, both as an average in the total amount of soil and only at the bottom of each column. The overall removal was around 2%, 66%, and 72% for NA, BS and BS + IN, reduced to 0%, 48%, and 47%, respectively, if measured only at the bottom. For the biostimulated mesocosms, the speciation of the hydrocarbons was carried out to assess their concentration. The findings evidence the need to delve deeper into this issue and assess the speciation of contaminants. [ABSTRACT FROM AUTHOR]

There has been a growing perception of organic pollutants as a threat to the environment. Because of their high persistence in the soil and significant toxicity at extremely low levels of exposure, organic contaminants pose a constant threat in the ecosystem. The most prevalent categories of organic pollutants found in the environment are pesticides, dye pollutants, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dichlorodiphenyltrichloroethane etc. However, researchers have gathered a great deal of knowledge about the source, pathways of contamination to the environment, interactions with constituents, impact on soil microbes and degradability by plants, uptake by plants, and contamination of food. The multifaceted effects on the ecosystem include contaminated food, water, and air, decreased soil enzyme activity that disrupts nutrient transformation processes, decreased biodiversity, and mutagenicity in microorganisms, among other things. Nonetheless, the review covered the origins, effects, and eventual disposal of organic pollutants within the ecosystem. [ABSTRACT FROM AUTHOR]

Arsenic contamination of soil and water is a major environmental issue. Bioremediation through plant growth-promoting bacteria is viable, cost-effective, and sustainable. Along with arsenic removal, it also improves plant productivity under stressful conditions. A crucial aspect of such a strategy is the selection of bacterial inoculum. The described study demonstrates that the indigenous wastewater isolate, ASBTKP1, could be a promising candidate. Identified as Klebsiella pneumoniae, ASBTKP1 harbors genes associated with heavy metal and oxidative stress resistance, production of antimicrobial compounds and growth-promotion activity. The isolate efficiently accumulated 30 µg/g bacterial dry mass of arsenic. Tolerance toward arsenate and arsenite was 120 mM and 70 mM, respectively. Plant biomass content of Vigna radiata improved by 13% when grown in arsenic-free soil under laboratory conditions in the presence of the isolate. The increase became even more significant under the same conditions in the presence of arsenic, recording a 37% increase. The phylogenetic analysis assigned ASBT-KP1 to the clade of Klebsiella strains that promote plant growth. Similar results were also observed in Oryza sativa, employed to assess the ability of the strain to promote growth, in plants other than V. radiata. This study identifies a prospective candidate in ASBT-KP1 that could be employed as a plant growth-promoting rhizoinoculant in agricultural practices. [ABSTRACT FROM AUTHOR]

Background: Environmental soil contamination is a serious problem for humans worldwide, as it causes many diseases. Methods: The present study focuses on utilizing biosurfactants produced by Pseudomonas stutzeri (P. stutzeri) NA3 and Bacillus cereus (B. cereus) EN6, as an electrolyte for removing chromium (Cr) from contaminated soil using the electrokinetic (EK) process. Results: As a result, biosurfactants produced by P. stutzeri NA3 and B. cereus EN6, being lipopeptides, increase heavy metal mobility in the EK process. The Cr removal efficiency of a novel electrolyte (biosurfactants) in the EK process was compared with that of NA3 and EN6 biosurfactants. The EK results revealed a maximum Cr removal of 75 and 70% by NA3 and EN6, respectively, at the end of 7 days. Discussion: The biosurfactant aids in the breaking down of the heavy metals that are present deeper into the soil matrix. From the metagenomics analysis, it was identified that biosurfactant changes the microbial community with an enhanced ability to remove heavy metals. The phytotoxicity assay confirms that NA3 biosurfactant solution showed 95% seed germination and can lower hazardous pollutants in the soil. Conclusion: The application of biosurfactants as a potent electrolyte for the remediation of hazardous pollutants is an integrated process. Overall, the results of this study suggest that biosurfactants can serve as an economic and efficient electrolyte in the EK process to remove Cr from polluted soil. [ABSTRACT FROM AUTHOR]

The paper considers the methodological approaches to the use of waste rock dumps of mining enterprises as elements of regional ecological networks. Such use of dumps will promote their biological reclamation and application of measures aimed at prevention of erosion and pollution of soil cover of agricultural lands located in the zone of influence of dumps. The aim of the research was to develop a methodology for the selection of waste dumps for their inclusion in the ecological networks of Ukraine. The objects of the research were waste dumps of coal mines of the Donetsk coal basin (Donbas). The main research method is the analysis of space images using Google Earth tools. It is shown that in the conditions of the lack of forest and land resources, waste dumps can be used in the ecological network of coal mining districts and towns not only as "restorable territories", i.e. reserve territories, but also as "interactive elements" of "key territories" ("natural kernels") and ecological corridors. A three-stage scheme for assessing the suitability of waste dumps as elements of the ecological network is proposed, which includes 3 indicators of the suitability of dumps for the requirements of restorable territories, 2 indicators of the suitability for the requirements of kernels, and 2 indicators of the suitability for the requirements of interactive elements. The system of evaluation of dumps in points for their ranking by the order of their inclusion in the schemes of the local ecological network is developed. Biological engineering measures have been proposed to better integrate the dumps into the local ecological network. These measures will result in improved protection of agricultural land from pollution, water and wind erosion. [ABSTRACT FROM AUTHOR]

Mercury pollution in emerging industrial zones and surrounding areas, especially in industrial concentration areas, has attracted much attention. So as to clarify the characteristics of Hg in the environment in China's small and medium-sized industrial emerging and surrounding areas, central urban area of Gongzhuling, a traditional agricultural town with a high degree of industrialization in northeast Changchun industrial base, is taken as the scope. Geological accumulation trin (Igeo) was used to study the degree of soil mercury contamination in Gongzhuling area, latent Er (ecological risk) trin was used to appraise the Er of soil Hg in the study area, and non-carcinogenic risk assessment of mercury in soil using human exposure risk assessment model. The results showed that 34% of soil samples had higher Hg content than the background value of the province's soil (0.04 mg kg-1). The Igeo results showed that Hg pollution rate of soil in study area was 9% (index >0). In conclusion, the level of soil Hg pollution in Gongzhuling area was low, and the pollution area is mainly concentrated in the northwestern part of the study range. The highest and lowest Er values of soil Hg from the study sample were 2.23 and 214.83, and 24% of the samples had Er > 40, that means they pose a moderate or higher potential ecological risk, and most of these points are located in the northeast of the study range. The main route of human exposure to Hg is oral ingestion. The HQ (non-carcinogenic risk index) and HI (total non-carcinogenic risk value) of soil mercury were both much less than 1, it indicates that the present level of soil Hg in the study range does not pose a threat to local adult health for the time being. This study provides reference for other urban pollution risk assessment, and further defines the direction of future work. [ABSTRACT FROM AUTHOR]

Encapsulation and nutrient addition in bacterial formulations have disadvantages concerning cell viability during release, storage, and under field conditions. Then, the objective of this work was to encapsulate a bacterial consortium with hydrocarbon-degrading capacities in different matrices composed of cross-linked alginate/ polyvinyl alcohol /halloysite beads (M1, M2, and M3) containing nanoliposomes loaded with or without nutrients and evaluate their viability and release in a liquid medium, and soil (microcosmos). Also, evaluate their capacity to remove total petroleum hydrocarbons (TPH) for 165 days and matrices characterization. The encapsulate consortium showed a quick adaptation to contaminated soil and a percentage of removal (PR) of TPH up to 30% after seven days. All the matrices displayed a PR of up to 90% after 165 days. The matrix M2 displayed significant resistance to degradation and higher cell viability with a PR of 94%. This result supports the encapsulation of bacteria in a sustainable matrix supplemented with nutrients as a well-looked strategy for improving viability and survival and, therefore, enhancing their effectiveness in the remediation of hydrocarbon-contaminated soils. [ABSTRACT FROM AUTHOR]

Pb soil pollution poses a serious health risk to both the environment and humans. Immobilization is the most common strategy for remediation of heavy metal polluted soil. In this study, municipal sewage sludge was used as an amendment for rehabilitation of Pb-contaminated soils, for agricultural use, near a lead-acid battery factory. The passivation effect was further improved by the addition of phosphate fertilizer. It was found that the leachable Pb content in soils was decreased from 49.6 mg kg−1 to 16.1–36.6 mg kg−1 after remediation of sludge for 45 d at applied dosage of municipal sewage sludge of 4–16 wt%, and further decreased to 14.3–34.3 mg kg−1 upon extension of the remediation period to 180 d. The addition of phosphate fertilizer greatly enhanced the Pb immobilization, with leachable Pb content decreased to 2.0–23.6 mg kg−1 with increasing dosage of phosphate fertilizer in range of 0.8–16 wt% after 180 d remediation. Plant assays showed that the bioavailability of Pb was significantly reduced by the soil remediation, with the content of absorbed Pb in mung bean roots decreased by as much as 87.0%. The decrease in mobility and biotoxicity of the soil Pb is mainly attributed to the speciation transformation of carbonate, Fe-Mn oxides and organic matter bound Pb to residue Pb under the synergism of reduction effect of sludge and acid dissolution and precipitation effect of phosphate fertilizer. This study suggests a new method for remediation of Pb-contaminated soil and utilization of municipal sewage sludge resources. [ABSTRACT FROM AUTHOR]

Coupled effects of biochar and antibiotic degrading bacterial strain on remediating contaminated soils with both heavy metals and antibiotics are poorly understood. A novel bio-based material combing an antibiotic degrading bacterial strain Herbaspirillum huttiense (HHS1) with biochar derived from spent mushroom substrate (BSMS) was developed, and an orthogonal test was conducted on soil contaminated with heavy metals and veterinary antibiotics. The stabilization of copper (Cu) and zinc (Zn) and the removal of oxytetracycline (OTC) and enrofloxacin (ENR) by the novel material at different temperatures were determined. Results indicated that the combination of BSMS and HHS1, along with temperature, was vital for pollutant treatments. The immobilized HHS1 (2 wt%)-BSMS (10 wt%) pellets achieved great stabilization efficiencies of Cu (69.2%) and Zn (59.72%), whereas higher removal of OTC (41.87%) and ENR (42.91%) was observed using HHS1 liquid and BSMS without entrapment at 35 ℃. The degradation of OTC and ENR by HHS1 accounted for 44.7% and 50.0% of their total removal, respectively. Oxytetracycline and ENR could be broken into small molecule products under low pH and high temperature through mechanisms including carbonylation, dihydroxylation, and piperazine ring-opening etc. When considering Cu and Zn stabilization, together with OTC and ENR removal in soils simultaneously, immobilized HHS1 (2 wt%)-BSMS (10 wt%) pellets are suitable for animal farms, even at low temperature (15 ℃), acting as an important bioresource for effectively stabilizing Cu and Zn and removing OTC and ENR in soil. [ABSTRACT FROM AUTHOR]

In recent years, organic pollution in soil has become more serious, thus timely treatment is particularly important. Persulfate technology has a good treatment effect in reducing soil organic pollutants. Analyzing the feasibility and prospects of the applications of persulfate technology in soil organic pollution is conducive to the development of soil remediation. The activation method of persulfate treatment of soil organic pollutants is as follows: thermal activation, microwave activation, ultrasound activation, alkali activation, material activation, electroactivation and photoactivation. The influencing factors of persulfate treatment of soil organic pollutants are as follows: coexisting substance effects, persulfate initial concentrations, treatment time, soil temperature, soil pH value and soil moisture content. Persulfate technology can effectively deal with the problem of organic pollution in soil, which can be developed in the following aspects: (i) Coupling different persulfate activation technologies; (ii) Applicating activated persulfate with non-metallic activated materials in soil remediation; (iii) Coupling different soil remediation technologies with persulfate; (iv) Preparating persulfate sustained-release materials for soil remediation. This work provides a reference for those who are concerned about the field of remediation of organic pollution in soil by persulfate. [ABSTRACT FROM AUTHOR]

Microbially induced carbonate precipitation (MICP) provides a novel idea to solve the problem of reduction and stabilization of Cr(VI) in contaminated soil. In this study, the remediation of Cr(VI) in severely polluted soil (total Cr = 5530.00 ± 120.21 mg/kg) by MICP technology combined with the Cr(VI)-reducing bacterium Sporosarcina saromensis W5 was systematically investigated. The results indicated that in W5 and CaCl2 treatment after 35 d of remediation, the Cr in exchangeable fraction could be converted into the oxidizable fraction (F3) and the proportion was 41.49%. Compared to original Cr(VI)-contaminated soil, the content of organic matter and soil urease were enhanced after remediation, indicating the improvement of soil quality. The increase in pH also facilitated the formation and stabilization of carbonate precipitation. In addition, the characterization results showed that Cr(VI) in soil was first reduced to Cr(III), and then formed Ca10Cr6O24(CO3) coprecipitation with CaCO3. The stabilization mechanism of Cr(VI) contained bioreduction, adsorption/complexation, and coprecipitation. The results of this study proposed an efficient and reliable strategy of Cr(VI)-reducing bacterium combined with MICP technology to reduce and stabilize Cr(VI) in high concentration Cr(VI) contaminated soil. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) have emerged as a pervasive environmental pollutant, posing significant threats to both aquatic and terrestrial ecosystems. Despite the growing concern, research on the impacts of MPs on soil ecosystems, particularly on crucial processes like nitrogen cycling, remains limited compared to aquatic environments. This study aimed to fill this knowledge gap by conducting a 60-day incubation experiment to investigate the effects of polypropylene (PP), polyethylene (PE), and polyethylene terephthalate (PET) microplastics on soil nitrogen transformation processes. The findings revealed that microplastic contamination influenced soil nitrogen dynamics, with PP having the most detrimental impact. Specifically, the ammonification rate was consistently lower than the nitrification potential, and although the nitrification potential was not negatively affected by the presence of MPs, the availability of soil nitrogen, particularly in the form of nitrate, was predominantly maintained. However, at the end of the incubation period, soils contaminated with PP showed a significant reduction in available nitrogen concentrations. Generally, it was found that PP had the most negative effect on soil nitrogen processes. These results underscore the varying effects of different types of microplastics on soil nitrogen processes, highlighting the critical need for further investigation into their long-term environmental impacts. [ABSTRACT FROM AUTHOR]

Against the backdrop of global warming, the pollutants that were once “temporarily stored” in the permafrost are gradually being released, posing significant impacts on the environment. This has become an internationally focused hot topic. In this study, the contents of 11 elements such as As, Ti, Cd, Cr, Co, Mn, Cu, Pb, Ni, Zn and V in soil samples from 128 sampling points in the freeze–thaw area of the Tuotuo River in the source region of the Yangtze River on the Qinghai-Tibet Plateau were determined to evaluate the possible sources, contamination status and ecological, environmental and health risks of these elements. The mean values of As, Cd, Pb and Zn were higher than the corresponding Tibet soil background values. Among fourteen PTEs, As, Cd and Pb had the highest average values of enrichment factor and pollution index, indicating that freeze–thaw area soils showed moderate enrichment and pollution with As, Cd and Pb. Mean ecological risk factor (ER) of Cd was 109 and other PTEs mean ER values < 40, whereas ecological risk index (RI) values of all PTEs ranged from 59.5 to 880 and mean RI values was 152, indicating moderate ecological risk in study area. Explanatory power q value of total S (TS) content was 0.217 by GeogDetector, indicating TS was the most significant contributing factor to RI. Correlation analysis and PCA analysis showed that Cr, Cu, Ni, Co, Mn, Ti, V were mainly originated from natural sources, Cd, Pb and Zn from traffic activity, As from long-distance migration-freeze–thaw. [ABSTRACT FROM AUTHOR]

Multilayer composite soil chamber was proposed to extract the Cr of contaminated site soil and insight into transformation of Cr fractionation associated with valence states. The variations of current, soil pH and moisture content were explored, as well as the migration of Cr fractionation and redistribution of Cr. Results indicated that duration of half peak current could be used to adjust treatment time and it varied among different composite ways. Moreover, extraction efficiency of Cr in soil near cathode was relatively higher and reached 60% when citric acid was used. Citric acid could promote the transformation between different Cr fractionations or different valence states. It could also improve the desorption of Cr, and could prevent excessive fluctuations of moisture content at the same time. Cr redistributed acrossed the soil chamber after extraction. When deionized water was used, Cr(VI) significantly migrated toward anode mainly in the form of exchangeable fractionation (EXC) while Fe–Mn oxides fractionation (Fe–Mn) which may be in the form of cationic Cr(III) hydroxides migrated toward cathode. When using citric acid, fractionations that were difficult to migrate of Cr, especially for Fe–Mn in site soils could be activated and became EXC and carbonate fractionation (CAR), then migrated to the anode or cathode. The migration of exchangeable Cr(III) was dramatically enhanced. But the use of citric acid could cause Cr(VI) transformation to Cr(III) near anode. In addition, during the migration process, EXC could go back to Fe–Mn again or transform to residue fractionation (RES). [ABSTRACT FROM AUTHOR]